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Biomedical subjects

W Ferreira

Publications and source records attributed to W Ferreira.

11 recordsLinked to original sources
PubMed2001

Hyperalgesia and edema responses induced by rat peripheral blood mononuclear cells incubated with carrageenin.

The aim of this study was to verify the role played by mononuclear cells in an acute (nonimmune) inflammatory reaction. Mononuclear cells purified from rat peripheral blood were incubated for 1, 2, or 24 h with 100 or 250 microg/ml carrageenin (Cg). The resultant donor supernatant was injected into recipient rats to test its ability to induce hyperalgesia (reduction in threshold for paw pressure) and edema (increase in paw volume). Mononuclear cell supernatants (MnS) induced a significant time- and dose-dependent hyperalgesia and edema in rat paws, which reached a maximal effect at 3 h, lasted for 6 h, and returned to basal levels at 24 h of injection. Prostaglandins and cytokines (interleukin 1, 2, 6, 8, and tumor necrosis factor alpha) accounted for the hyperalgesia induced by MnS, as it was reduced (40 to 90%) by synthesis inhibitors such as indomethacin, dexamethasone, rolipram, and cyclosporin added to the cultures at a microgram dose-range. Edema was dependent on serotonin release in rat paws. These results indicate that mononuclear cells may be important contributors to acute inflammatory reactions, especially under those conditions where pain is an important component.

Animals↗
PubMed1992

Glutamatergic postsynaptic block by Pamphobeteus spider venoms in crayfish.

The effects of toxins from venom glands of two south american spiders (Pamphobeteus platyomma and P. soracabae) on glutamatergic excitatory synaptic transmission were studied in the neuromuscular junction of the opener muscle of crayfish. The toxins selectively and reversibly blocked both excitatory postsynaptic currents and potentials in a dose-dependent manner. They also reversibly abolished glutamate-induced postsynaptic membrane depolarization. They had no effect on resting postsynaptic membrane conductance nor on postsynaptic voltage-gated currents. The synaptic facilitation and the frequency of miniature postsynaptic potentials were unaffected by the toxins, indicating that presynaptic events were not modified. Picrotoxin, a selective antagonist of the gamma-aminobutyric acid (GABA)A receptor, did not modify toxin effects. We conclude that both toxins specifically block the postsynaptic glutamate receptor-channel complex.

Animals↗
PubMed1980

Aortic valve replacement in preteenage children.

During the last 15 years, 26 children who ranged from 4 to 12 years old underwent subcoronary aortic valve replacement (AVR) at the Texas Heart Institute. The valve lesions resulted from congenital heart disease in 20 patients, 15 of whom had had a previous operation including 13 aortic valve procedures. Cystic medial necrosis necessitated AVR in 5 patients, all of whom had physical findings of Marfan's syndrome. One patient had rheumatic heart disease and required double-valve (aortic and mitral) replacement. Six different types of prosthesis were used: the Smeloff-Cutter, Starr-Edwards, Cooley-Cutter, Hancock porcine, Ionescu-Shiley, and Bjork-Shiley. The first patient in the series was the only early death (3.8%). Log-term follow-up data ranging from 1 month to 10 years were available on 20 patients. Three late deaths occurred (11.5%). All survivors are doing well and have good exercise tolerance. These data suggest that AVR performed in childhood is a safe, durable, and well-tolerated form of therapy. Later replacement, if necessary, can be accomplished with larger-sized prostheses. Our present choice is the Ionescu-Shiley bovine xenograft because of its superior hemodynamic characteristics and low incidence of embolic complications.

Age Factors↗
PubMed1969

Origin and progress of the 1968-69 Hong Kong influenza epidemic.

The Hong Kong strain of influenza virus A2 may have originated in the mainland of China but this is not certain. It caused a very large epidemic in Hong Kong and spread rapidly to countries as far as India and the Northern Territory of Australia-as happened in the 1957 epidemic. Later its progress slowed down but epidemics occurred in many countries in the northern hemisphere in the winter of 1968-69. In all these countries except the United States of America the disease was mild and not associated with a large increase of deaths. In the United States of America, however, the number of "excess deaths" was similar to the number in 1957-58.In the southern hemisphere epidemics began in May-June 1969; they have been clinically mild and the reported incidence of disease has been only moderately high.In many countries the infection has spread slowly and smouldered instead of bursting into the usual sharp epidemics.The smouldering spread and the contrast in the behaviour of the disease in the USA compared with the rest of the world are the outstanding features of the Hong Kong strain of virus. Satisfactory explanations of these observations might lead to the development of more effective means of control of influenza.

Disease Outbreaks↗
PubMed1967

WHO collaborative study on the sero-epidemiology of rubella.

Under the auspices of WHO an investigation was made by 9 laboratories in different parts of the world on the distribution of rubella antibodies in girls and women of child-bearing age. In the first part of the study the objective was to determine the reliability and reproducibility of the tests employed. It was found that there were no significant differences in the variability of the titres obtained in different laboratories when the results were compared with those obtained by repeatedly testing the same sera in one laboratory.In the second part of the study sera were obtained from girls in schools and women attending clinics and health centres. They were not taken from random samples of the populations. In most of the studies the pattern of development of antibody was similar. About half the persons had antibody at 6-8 years of age and 80%-87% at 17-22 years of age, the percentage remaining relatively constant thereafter. The island populations of Trinidad and Jamaica and a rural area of Japan were, however, found to have significantly fewer women with antibodies than urban areas in Europe or the Americas.

Adolescent↗
PubMed1967

WHO respiratory disease survey in children: a serological study.

This paper is a report on the first (serological) phase of a study organized by WHO in collaboration with the WHO International Reference Centre for Respiratory Virus Diseases other than Influenza in Bethesda, Md., USA, to define the viral etiology of severe respiratory infections in children, particularly in tropical areas. Paired sera from 528 children up to 5 years old admitted to hospital with severe respiratory illness of probable viral etiology were collected in 10 countries and sent frozen to the International Reference Centre, where standard complement-fixation tests were made for the following agents: parainfluenza virus types 1, 2 and 3, influenza virus types A and B, adenoviruses, respiratory syncytial virus, Mycoplasma pneumoniae, Coxiella burneti and psittacosis-ornithosis.Some 41% of paired sera showed rising antibody titres for one or more of these agents, multiple infections being observed in 8%. In most of the countries the pattern of infection was similar. RS virus was the most important respiratory tract pathogen of early life, particularly in the first year of life and in cases of bronchiolitis and pneumonia; the parainfluenza viruses were next in importance, particularly in cases of croup, but, in contra-distinction to RS virus infections, they were commoner in older children. Influenza, adenoviruses, and M. pneumoniae were of moderate importance, and C. burneti and the psittacosis-ornithosis agents were relatively rare. This pattern is similar to that which has been observed in temperate climates.

Africa↗